I agree. Though, isn't symbiosis - that you mentioned - basically about selfish (beneficial) intents from both parties?
Too much selfishness creates what you said, selflessness only benefits the other party. There's a healthy limit to it in this case.
I made a comment before, but I want to comment on this ongoing "selfishness discussion" too.
I think we can all agree that people should have the right to spend their money on what they want, not what the game developer wants, right? If it is selfish to want to have control of your own money, then so be it.
As for these expansions vs. DLC --> Beth is a company. As a company they want to make money. They can either put out lots of cheap DLCs and get people to buy a bunch, or they can put out one or two good expansions that cost more like $30 than $5. Whichever practice generates more revenue is the one Beth will pursue. As long as they make more money with cheap DLCs than with good (and more expensive) expansions, we're going to keep getting cheap DLCs.
I for one do not buy cheap DLCs if I hear they svck. I won't spend my money on them. I will, however, spend money on drawn out and well developed expansions. Beth will do what the market wants, all we can do is say what we want and back that up with our purchasing. If we say we want expansions, but keep buying DLCs, we won't be getting expansions any time soon.